Generally, a device-to-device (hereinafter abbreviated D2D) communication literally means a communication between one electronic device and another electronic device. In a broad sense, the D2D communication may mean a wire/wireless communication between electronic devices or a communication between a human-controllable device and a machine. Recently, the D2D communication may generally indicate a wireless communication between electronic devices performed without human involvement.
In the early 1990's, in which the concept of the D2D communication has been initially introduced, the D2D communication has been recognized as remote control or telematics or the like and derivative markets of the D2D communication were very limitative. Yet, the D2D communication has grown rapidly for past few years and has become the globally noteworthy markets. Specifically, in POS (point of sales) and security related application markets, the D2D communication has considerably influence on such field as fleet management, remote monitoring of machinery and equipment, smart meter for auto-measurement of operating time, consumed heat or electricity quantity on construction machinery equipment and the like. D2D communication in the future will be further utilized for various usages in connection with a small-scale output communication solution such as conventional mobile communication, wireless high-speed internet, Wi-Fi, ZigBee and the like and may lay the foundation of expansion to B2C (business to consumer) markets instead of being confined to B2B (business to business) markets.
In the era of D2D communication, since all machines in which a SIM (subscriber identity module) card is installed are eligible for transmitting and receiving data, a user may remotely manage and control the machines. For instance, a D2D communication technology can be applied to such a wide scope as a vehicle, a truck, a train, a container, a vending machine, a gas tank and the like. Yet, a study on a D2D communication scheme including a base station and D2D user equipments is not entirely satisfactory.